(In [10193]) Fixed #8462 -- Made length and length_is template filters fail silently when given a value that has undefined length and added tests for both filters. Based on patch from marcelor, rob, and SmileyChris.

(In [10194]) [1.0.X]: Fixed #8462 -- Made length and length_is template filters fail silently when given a value that has undefined length and added tests for both filters. Based on patch from marcelor, rob, and SmileyChris.